With the recent advances in Internet content distribution, including peer-to-peer networks and real-time video streaming systems, in order to prevent unauthorized distribution of content, it becomes important to embed data in video to trace the point of distribution. The point of distribution is often an authorized viewer, such as a cinema where pirated copies are made with camcorders, or a set-top-box TV decoder whose output is captured and re-encoded into a video file. After tracing the source, measures can be taken to prevent further unauthorized distribution.
Embedding signals in video is a rich field both in academic research and commercial inventions. Covert watermarking in the video is well known in the art, as are overt watermarks that appear as bitmaps on top of the video, and steganographic watermarks.